Generally, phosphors are classified into white, red, green, yellow and blue phosphors, and among them, red(R), green(G) and blue(B) phosphors are mainly used for display devices such as CRT.
Red phosphor is produced by firing raw materials of the red phosphor, washing the resulting fired material, ball-milling the washed material, coating the material with pigments, drying and then sieving the material.
Green and blue phosphors are produced by firing raw materials, washing the resulting fired material, ball-milling the washed material, surface-treating with various silicate compounds and then sieving the material. That is, in the conventional phosphor producing method, the ball-milling process is indispensably carried out to reduce the amount of aggregated particles and to disperse the phosphor materials. However, there is a problem in that the brightness of the phosphor seriously decreases during the ball-milling process.